Invest everything today, or spread the same total over monthly installments? Both sides contribute exactly the same money; only the timing differs, so the comparison is honest. The year-by-year table shows the gap widening with compounding.
The uncomfortable truth the tool shows: with a positive expected return, lump sum wins on average (markets rise more often than they fall — historically about two years in three). DCA wins in falling markets, reduces regret, and enforces discipline.
Frequently asked questions
So DCA is pointless?
No — it is a risk-management tool, not a return maximizer. If a lump sum would keep you up at night, the peace of mind is worth the statistical cost.
Does it account for volatility?
The math assumes a steady average return. Real markets wobble, which widens the spread of DCA outcomes without changing its average much.
中文说明
今天一次全投，还是把同样的总额按月分批？两边投入完全相同，差别只在时间——这样的对比才诚实。逐年表格能看到复利把差距越拉越大。
工具会展示一个不太舒服的事实：预期收益为正时，一次性投入平均而言胜出（市场涨多跌少——历史上约三年里有两年）。下跌市里定投占优，还能减少懊悔、强制纪律。
常见问题
所以定投没意义？
不是——它是风险管理工具，不是收益最大化工具。如果一次性投入让你睡不着觉，这份心安值得那个统计上的代价。
考虑波动吗？
计算假设收益率恒定。真实市场会震荡，这会拉大定投结果的分散度，但不太改变其均值。